STI Stopper II® with Horn Flush Mount (Indoor/Outdoor Rated), Fire ...

STI STI-1150 Stopper II Protective Cover

Overview

The STI-1150 is a flush-mount polycarbonate protective cover designed to prevent false fire alarm pulls while preserving legitimate emergency activation. The unit combines a clear, tamperproof shield with an integrated piezo horn powered by a 9VDC alkaline battery, making it suitable for schools, hospitals, nursing homes, hotels, and public buildings where accidental or intentional false alarms pose operational and cost risks. This model is rated for both indoor and outdoor installation per UL standards for custom-labeled fire products.

Compatibility

The STI-1150 accommodates most standard manual pull stations. For larger pull stations or surface-mounted configurations, pair with the optional STI-3100 conduit spacer to maintain proper clearance and ADA design compliance. The 9VDC horn operates independently of the pull station mechanism, allowing retrofit installation on existing pull stations without modification to the station itself.

Installation Notes

When mounting outside, UL regulations require the underlying pull station to be listed for outdoor use. The cover operates across -40°F to 250°F (-40°C to 121°C), accommodating both heated and unheated environments. Weather models include closed-cell gaskets to manage moisture and temperature cycling. Battery replacement is straightforward — the 9VDC alkaline battery powers the horn and is included with standard models. For remote-powered applications, a line-powered variant is available.

What's in the Box

• 1x STI-1150 polycarbonate protective cover with frame
• 1x 9VDC alkaline battery (standard horn model)
• Mounting hardware (specifics per installation location)